Edit: I feel like if you have to explain the joke, it's a bad joke, lol, so I may delete this.
The "big bad" in Disco S4 is the Dark Matter Anomaly (basically a 5 light-year wide rogue black hole that destroyed a planet and mining colony and is on course to destroy more). They shorten it to DMA for brevity.
Currently trending in the news is the Digital Markets Act (an EU regulation) that's also abbreviated as DMA.
